Metal wobking machineby and method



March 8, 1932. w. B. PEIRCE 1,848,835

METAL WORKING MACHINERY AND METHOD Filed Nov.26, 1928 4/5 J19 ;,;1 A 15 {3 10 10 F 1 Gd! INVENTOR. William 15 Peirce.

Patented Ma. 8, 1932 WILLIAM BRADFORD PEIRCE, OF SEWICKLEY, PENNSYLVANIA; ASSIGNOR TO PITTS- BURGDI SG'REW Eo BOLT CORPORATION, OF PITTSBURGH,

PORATION OI PENNSYLVANIA METAL WORKING MACHINERY AND METHOD Application filed November 26, 1928. Serial No. 321,840.

The present invention relates to metal working machines and methods and may have a wide range of usefulness. It is particularly concerned, however, with the feeding of stock to the cut-off and forming mechanism of automatic machiner such, for instance, as feeding hot bar stoc to the cut-ofi and forming mechanism of an automatic nut machine.

As opposed to the older methods of feeding hot bars by hand to the forming machinery, automatic feeding mechanisms have been proposed, one of which is disclosed 1n m copending application, Serlal No. 170,816, filed February th, 1928, which 1ssued July 2, 1929, as Patent No. 1,719,446.

Such a mechanism efl'ects intermittent forward feeding steps of the stock bar alternating with intermediate bar withdrawing steps. It provides means for automatically retracting the stock through a desired accurately predetermined distance and then advancing the same forwardly through a distance equal to the distance of retraction plus the length of the stock required for the next blank.

In accordance with the present invention I have discovered that such extreme accuracy in the feed is unnecessary, and have devised a stock feeding means and method which obviates the necessity for positively withdrawing the stockbar between slug-cutting operations, whereby considerable economy of power is effected and production is materially speeded up by the elimination of the retrograde or idle'movements of the stock.

In accordance with the present method I use an intermittent overfeeding motion embodying feed rolls having stock-feeding means or lands thereon which are operative to feed the bar through a considerably greater distance than the length of stock required for a blank. The feed rolls grip the stock with suflicient friction and pressure to assure a comparatively positive movement of the stock against a stopgauge. Thereafter the feed portions of the rolls are free to slip and during the latter portion of their engagement with the stock simply act as friction clamps to hold the bar while a slug is being cut. After the cutting operation the feed portions of the rolls pass completely out of engagement with the stock leaving the latter free so that it will cause no heavy drag on the forming tools which operate upon the cut blank.

The present invention also is concerned with the provision of stock feedin mechanism which makes the introduction of a fresh bar to follow up the stub end of a partially used one a semi-automatic operation and obviates the possibility of an operator, when feeding in anew bar, shoving the end of the old one between the formingtools at the wrong time.

The invention may be more fully understood from the following description in con-.

nection with the accompanying drawings, wherein: I

Fig. 1 is a plan view of a stock bar and feeding mechanism with the conventional stock cutting and forming tools shown in section.

Fig. 2 is a side elevational view of the apparatus shown in Fig. 1, showing the position of the parts after a blank has been cut and with the stock bar clearing the forming too s.

Fig. 3 is a-view similar to Fig. 2 but highly diagrammatic, showing the position of the feed rolls as they arethrowing the bar forwardly toward the gauge and showing also the manner in which a following bar is introduced. Fig. 4 is a view similar'to Fig. 3 but showing the position of the parts just after a blank has been cut and after the feed rolls have caused the following bar to catch up to the stub end of the previous bar.

Fig. 5 is a view similar to Fig. 4: but showing the position of the feed rolls just after they have engaged the stock and started to thrust it forwardly.

The drawings are slightly diagrammatic throughout, in that the driving mechanism for the feed rolls and operating mechanism for the cutting and forming tools are omitted. Figs. 3 to 5 also omit all showing of guides and roller mountings and other details for the sake of simplifying the showing. The drawings also omit any showing of the fur- IPENNSY LVANIA, A COR- nace through v.which stock bar 10 is passed and in which the stock bar 10 may remain until it is sufiiciently heated to be manually pushed out to the feed rolls. It may be stated that the illustrated nut blank cutting,

' crowning, piercing and ejecting mechanism is entirely conventional and represents the cutting and forming mechanism of a machine which is practically standard in the art.

The conventional parts of the illustrated mechanism include in addition to the stock bar 10 the stop gauge 11 against which the end of the stock is pushed and held. The cut-off unch 12 which severs the blank and pushes 1t into the pocket 13 where the blank is crowned by being squeezed between the cut-off 12 and the hollow crowner 14. Piercer 15 moves through the hollow crowner and punches the hole in the blank, forcing the removed slug section into the pocket 16 in the end of the cut-off 12. Upon subsequent retraction of the cut-off the stationary kicker 17 ejects the slug which has been formed by the piercer and as the piercer withdraws the crowner 14 moves forward, ejects the completed nut blank, and is again withdrawn ready for the next feed of the stock.

My present invention is more particularly concerned withthe means for overfeeding the stock, frictionally holding it while it is being cut and then releasing it so that it will not drag on the forming tools.

This feed mechanism includes two pairs of feed rolls 18, 18 and 19, 19. The stock passes along a guide trough 30, first between the pair of rolls 18 and then between thepair of rolls 19. The rolls 18 and 19 may be of identical construction. They are continuously rotating in the direction indicated by the arrows and each roll includes a raised portion or land 20, these lands serving as the stock feeding portions of the rolls and their totalefiective feeding length being considerably in excess of the length of stock required for a blank. The rolls are arranged so that they grip the stock quite firmly at each revolution and force it inwardly against the stock gauge 11.

In order to compensate for slight variations in the thickness of the stock to be handled, at least one roll of each feeding pair is yieldingly mounted. Preferably, the other roll serves to lift the, stock off the bottom of the guideway, and thereby decrease frictional resistance to the forward sliding movement of the stock bar.

The means illustrated in Figs. 1 and 2 for effecting the spring gripping and stock lifting action are quite diagrammatic and subject, of course, to many variations and refinements in practice.

Each pair of feed rolls (including fore and rear rolls) is mounted in a frame straddling the guide trough 30. The lower roll of each pair is mounted on an axle 41 journalled in the frame and the lands 20 of these rolls work through slots 42 in the guideway and slightly lift the stock. The bearings 43 and axles 44 for the upper rolls are vertically slidable in guideways provided by the frames 40. Pressure plates 45 are adjustable by set screws 46- to properlytension coil spring 47 which urge the beari n s or crossheads 43 downwardly against adjustable fixed stops 48. V,

The overfeed serves to maintain a fric tional clamping engagement on the stock to hold it firmly against the gauge stop while the blank is beingcut. Thus on each feed stroke the feed rolls hold or grip the bar frictionally and puslnforce, or press it endwise against the stop, and the cut-off 12 severs the blank before the stock has been released by the lands 20 and while the feeding rolls are turning with the lands in engagement with the stock bar. Immediately after the blank-severing operation the lands 20 pass out of engagement with the stock, as seen in Fig. 2, so that the stock bar is fully released and free and it will oiferno appreciable drag on the tools.

The stock bars are heated in a furnace and pushed directly from the furnace into engagement with the first set of feed rolls 18. In accordance with the usual practice these bars are inserted in the back of the furnace by an operator and after they have been thoroughly heated are pushed out through the front of the furnace, into the flare-d guiding mouth 30a of the trough until the feed rolls grip them. When one stock bar, such, for instance, as the bar 10, has been substantially used up, as in Fig. 3 and a new bar 10a is being pushed into place behind it, there is a possibility of the bar 10a striking the rear end of the bar 10 and jamming the latter in between the forming tools at the wrong time. It is primarily to overcome this difficulty that I use the two sets of feed rolls. Thus, as seen in Fig. 3, it is merely necessary, after one bar has cleared the first set of feed rolls 18 and is being fed by the second set 19, to shove the new bar 10a forwardly to a point where the rolls 18 grip it. The operator, who is pushing this bar into place can of course readily tell when the rolls 18 have engaged the end of it since the mechanical feed will shift the bar at a considerably greater speed than the slow sliding movement which is being imparted thereto by a manual thrust.

Fig. 3 shows the position of the parts in which the feed rolls 19 are forcing the stub end of the bar 10 toward the forming mechanism and the feed rolls 18 have engaged the new bar 10a, but have not yet moved it into abutment with the end of the bar 10.

The overfeeding action of the lands 20 of the rolls 18 quickly takes care of moving the end of the new bar 10a into abutting relationship with the end of the old bar 10. In-

asmuch as bar 10 can never be moved forwardly through an effective distance greater than the length of the blank to be cut, and the bar 10a can be moved forwardly through the total feeding throw 10a will quickly catch up to the bar 10 and will subsequently serve as a pusher to force the remainder of this bar to the forming mechanism. As a matter of fact the speed of the feed rolls is such that when they release bar 100 it will continue to move forward under its own-momentum, being not only fed forward but actually picked up and thrown forward so that it will quickly catch the stub end of bar 10.

Fig. 4 shows the relativepositions of the two stock bars after the new one has caught up to the stub end of the old one and is push'ng it along. In Fig. 4 the stock is released by the feed rolls and in Fig. 5 the feed rollshave picked it up again-and are starting to feed it forwardly.

It will be perfectly obvious that the feed rolls, instead of each having a single land thereon might be of larger diameter and provided with a spaced series of lands so .that the bar engaging portions of the feed rolls may have more'opport-unity to cool between the stock-engaging intervals.

It will also be apparent that while I have shown dies 23 .of proper contour to form a square nut, the nature of these dies forms no part of the present invention. Any desired shape ofnutmay be formed in a similar manner without in any way altering the meth od andapparatus for feeding the stock and working apparatus.

such stock feed is well adapted for embodiment in handling hot rod or bar stock in connection with spike or bolt forming machines or generally analogous types of metal- From the standpoint of the present invention it is immaterial how the bar is guided between the feed rolls and the mechanism. For illustrative purposes only I have shown the guide trough 30 which prevents transverse bending of the stock as it is being fed and the overhanging end 30?) of which or an equivalent guide device fixed to the forming'machine affords support for the short stub ends of the stock bars after they have left the rolls.

In order to effect the ejection of completed nut blanks and the rejection of stock bar stubs which are too small for forming nuts I use a reciprocating knockout rod 50( In connection with the rejection 'of undesirable lengths of the .rolls '18, bar

forming apex as a. fulcrum, will swing downwardly I and drop outof the machine.

The spray nozzles 31 which are diagrammatically illustrated in Figs. 1 and 2 are conspray a cooling fluid on the forming tools without cooling the end of the stock'ba r.

In operation the feeding, mechanism which I have described is very rapid. Practically all of the movement of the stock is in a for- Ward direction and the stock bar is passed to the cutting and forming tools with such rapidity that the rear end of the bar does not have sumed by the machine. By reasonof the simplicity of movement and the accurate timing of grip and release of the bar 10 by the lands 20, it is possible to feed and cut the nut blanks at a rate of two to three per second a. chance to cool before it'is con- .ventional parts of the machineand serve to and even when running at a lower rate,,the vlolence of the movement of the machine and of the bar, plusthe early ing of the release-of the ar, insure complete,

punch. Moreover, onthe return movement and accurate tim-' of the tools and blank, any slivers or projec- I tions on the blank, or even vibration of the forming tools can be accommodated by the freedom with which the unclamped'bar may be slightly jarred or forced back endwise in the trough 30, 30a, 30b.

W hat I claim is 1. Means for feeding bar stock or the like endwise to a blank-cutting and shaping machine, including a pair of continuously rotating feed rolls, raised stock-engaging surfaces on the feed rolls operative to intermittently grip the stock and feed it forwardly, a stop and gauge limiting the forward feeding movement of the stock and positioning the end thereof in proper relationship to a blank cutter.

2. Means for feeding bar stock or the like endwise to a blank-cutting and shaping macnme, including a pair of continuously rotating feed rolls, raised stock-engaging surfaces on the feed rolls operative to intermittently grip the stock" and feed it forwardly, a stop and gauge limiting the forward feeding movement of the stock and positioning the end thereof in proper relationship to a blank cutter, the engagement between rolls and stock being such that upon engagement of the stock with the stop, continued turning of the rolls causes them to slip on the stock and frictionally hold it against the gauge during the cutting operation, then to release the stock and leave it free during subsequent forming operations. a

3. Means for feeding bar stock or the like endwise to a blank-cutting and shaping machine, including a pair of continuously rotating feed rolls, raised stock-engaging surfaces on the feed rolls operative to intermittently gri the stock and feed it forwardly, a stop and gauge limiting the forward feeding movement of the stock and positioning the end thereof in proper relationship to a blank cutter, the engagement between rolls and stock being such that upon en gement of the stock with the stop continue turning of the rolls causes them to slip on the stock and frictionally hold it against the gauge during the cutting operation, then to release the stock and leave it free during subsequent forming operations, one roll being spring tensioned to effect non-positive gripping and feeding of the stock.

4. Stock feeding means as set forth in claim 2 and including two spaced pairs of feed rolls whereby one pair may overfeed a new stock bar while the other feeds the stub end of an old one to the machine.

5. The combination with a stock feeding mechanism, of a pair of continually running feed rolls having lands alternately engaging and releasin the stock for feeding it intermittently, said ands having a total effective feeding length in excess of the length of stock required for a given blank, for causing frictional slippage of said lands on the stock whelr; the feed is limited to the length of the stoc 6. The combination with a stock feeding mechanism, of a pair of continually running feed rolls having means alternately frictionally engaging and releasing the stock for intermittently feeding it, said means having a total effective feeding length in excess of the length of stock for a given blank, and means for limiting the feed of the stock to the length of a given blank, so that the stock will be held for a period against said limiting means by slippage of said feeding means on the stock.

7. The combination with a-stock feeding mechanism, of a pair of continually running feed rollshaving lands alternately engaging it interh and releasing the stock for feedin mittently, said lands havin, a tota effective feeding length in excess of the length of stock required for a iven blank, a stop for limiting the feed of the stock to the length of a blank to be cut off, so that the stock will be held against said stop by slippage of said lands thereon.

8. The combination with a stock feeding mechanism, of a plurality of pairs of continually running feed rolls having lands al ternately engaging and releasing the stock for feeding it intermittently, said lands having a total effective feeding length in excess of the length of stock required fora given blank, a stop for limiting the forward movement of the stock produced by a pair of the lands, so that the stock will be held against said stop by sli page of said lands thereon, the rolls of all t e pairs moving stock in the same direction and rotating at the same speed, so that a piece of stock fed to a rear pair of rolls will be brought into abutting relation to the stock bein fed by a fore air of rolls when the forward pair has broug t the stock against said stop.

9. The combination with a stock feeding mechanism, of a pair of continually running feed rolls having lands alternately engaging and releasing the stock for feeding it intermittently, a trou h for guiding the feed of the stock, a stop or limiting the feed of the rolls, said lands having a total effective feeding length in excess of the length of stock for a iven blank, so that said lands will frictional y press the stock against said stop by slippage thereof, means for cutting off a blank from the stock while said lands are pushing the stock against said stop, and means for forming the blank after said lands have released the stock.

10. The method of feeding rod or bar stock to blank cutting and forming machinery, which includes moving the stock forward into cutting position, holding the stock by the force of forward movement while a blank is being cut from the end thereof, releasing the forward movement and loosely holding the stock while the blank is being formed.

11. The method of feeding rod or bar stock to blank cutting and forming machinery, which includes intermittently pushing the stock forward into cutting position, continuing to push and holding the stock by means of the pushing force, limiting the forward movement of the stock while a blank is being cut therefrom, thence, releasing the pushing force upon the stock, and loosely holding the stock while the blank is being/ formed.

12. The method of feeding rod or bar stock to blank cutting and forming machinery, which includes supporting the stock, intermittently pressing the stock forward into cutting position, holding the stock in a blank cutting position by simultaneously maintaining e forward pressure and limiting any actual movement of the stock, releasing the forward pressure after a blank has been cut from the stock, so that the blank may be formed.

13. The method of feeding rod or bar stock to blank cutting and forming machinery, which includes intermittently moving the stock forward into cutting position, maintaining the force of the forward movement and limiting the actual movement so that the stock will be held in a given position while a blank is being cut therefrom, releasing the force of the forward movement, and loosely holding the stock while a blank is being formed.

14. The method of feeding rod or barstock to blank cutting and forming machinery, which includes pressing the stock forward, maintaining the forward pressure and independently limiting the actual forward movement produced thereby while a blank is being cut from the end of said stock, releasing the forward pressure, and loosely supporting the stock while the blank is being formed.

15. The method of feeding rod or bar stock to blank cutting and forming machinery, which includes mtermittently moving the stock endwise by forward pressure, holding the stock in a blank-cutting position by maintaining the forward pressure and limiting the resultant forward movement thereof, and after a blank has been out 01f, releasing the forward pressure, and loosely supporting the stock while a blank is being formed.

16; The method of feeding a plurality of pieces of rod or bar stock to blank cutting and forming machinery, which includes intenmittently moving a plurality of pieces of stock endwise as a continuous piece into blankcutting position, maintaining the forward pressure and limiting the actual forward movement produced thereby while a blank isbeing-cut from the end of the stock, releasing the forward pressure, and loosely holding the stock during the forming of the 5 blank.

17 The combination wlth blank cutting and forming machinery having a stock feeding mechanism, of means moving the stock forward into cutting position, said means so pressing against the stock and thereby holding it while a blank is being cutfrom one end thereof and means loosely holding the stock while the blank is being formed.

18. The combination with blank cutting and forming machinery having a stock feeding mechanism, of means intermittently moving the stock forward, and additional means limiting the forward movement of the stock while a blank is being cut therefrom, and

means loosely supporting the stock after the' forward moving force has been released and while the blank is being formed.

19. The combination with blank cutting and forming machinery having a stock feed- 46 ing mechanism, of means supporting the stock, means intermittently moving the stock forward into cutting position, means limiting the actual movement of the stock while a blank is being cut therefrom, said forward 50 moving means having a surface contacting with the stock for moving it forward and a surface for non-contacting with the stock while the blank is being formed.

Signed at Coraopolis, in the county of Alle- 'heny and State of Pennsylvania, this 21st ay of November, A. D. 1928.

WILLIAM BRADFORD PEIRCE. 

